In a liquid crystal display panel, alignment films for aligning the liquid crystal are provided on opposite surfaces of an array substrate and a cell substrate. In the process of manufacturing the liquid crystal display panel, aligning agent is first applied to a substrate to form an alignment film, and then the alignment film is subject to a photo alignment or a rubbing alignment. At present, a device for applying the aligning agent can include an instilment structure 70, a distributing roller 80, a cylinder, and a transfer plate 20 surrounding the cylinder, as shown in FIGS. 1a and 1b. During the application of the aligning agent, the aligning agent is instilled onto the distributing roller 80, and then the distributing roller transfers the aligning agent onto the transfer plate 20. Subsequently, with a rotation of the cylinder, the aligning agent on the transfer plate can be transferred onto the substrate.
A wetting phenomenon occurs when liquid is brought into contact with a solid body. When a contact angle θ between the liquid and a solid surface is an acute angle, it can indicates that the solid surface inclines to be wetted by the liquid, that is, the solid surface has a good wettability (as shown in FIG. 1a); when the angle θ is an obtuse angle, it can indicates that the solid surface is not easily wetted by the liquid (as shown in FIG. 1b). To improve the wettability of a solid surface, a roughening process can be made to the solid surface. For the transfer plate, recesses in an array are usually arranged on its surface to hold the aligning agent to a certain degree. However, the transfer plate is made of resin material. At an early stage of use, the transfer plate may show a poor wettability, which has a strong impact on an amount of the aligning agent held thereon, such that the resulted alignment film may have a small thickness and a poor uniformity.